Portable watch charger!

Just weighed it, only 3.4 ounces (96g)

Wouldn't the cable it came with plus any battery pack providing 500mA-1A do the same job...?

Sure, there's nothing special about the cable, but I'd hate to permanently tie my only cable to a battery pack. And the battery pack I think strikes a good balance between size/weight and capacity. Any higher capacity would be unnecessary. Any lower capacity and it it could only charge the watch, and not much else.

I wish Garmin would release a quick fit carabiner strap at last (and some other quick fit accessories). So I could "mount" my device on the backpack strap during a hike and am able to load the device during the activity.

I had a Fenix 5x, smaller battery, so it would recharge quicker.   But during ultra runs, when I needed a recharge (usually only for ultras > 50 miles),  I would simply run holding the watch in my hand.  It recharged quickly, so its only 30 minutes or so.  Why in the hand?  so I would still approximate the swing of an arm.

If you have a hydration vest , its just as easy to fasten the watch to a strap there, or even in a flex pocket on them. 

A right angle plug wouldnt really even work unless you had the watch super loose anyway since even a thin right ankle would still a big bump-out compared to rest  of watch.

With the Fenix 6x battery, I dont expect to ever need a recharge unless I do another 100 miler, an even then it might actually last long enough (I'm not that fast

the need to have that watch on the wrist while charging is diminished with the larger battery methinks.. not completely.. but closer at least.

Check at home if it does work, a watch doesn't draw that much power, so some power banks don't take it serious and turn off early or don't charge all.

The one I own turns off at 90%. And I've read some even don't turn on at all with the low output it takes for the watch. 

One thing to note here is that when you do a "charge on the go", the OHR gets turned off, so it doesn't really matter if it's not on your wrist

Actually validate this for a few minutes.  I bought an Anker that was specifically described as able to power low draw devices and it goes off after about 60 seconds with my watch plugged in.   I have another no-name lipstick battery that works fine.   Go figure. 

Also, as I found on my first 100 with the 6X, using LiveTrack is a significant battery hit.  You will not get 60 hours of GPS if you have livetrack enabled.   More like 40 maybe.   After 26 hours, from 99% I was down to 24% battery left and live tracking the entire route. 

Possibly something to look into is this?  It'll provide less lateral stress on the cable and connector than the OEM cable sticking out at 90 degrees to the watch.   A wide rubber band would secure it pretty handily and if you have small to medium wrists you can fasten the watch to your wrist with this under it although the cable sticks out the wrong way if you wear it on your left. 

https://www.amazon.com/gp/product/B07PBW23XJ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Good point - I haven't had a chance to try it yet because my watch still has an almost full charge, it might be a week or so before the battery gets low enough to give this a try.